A group of researchers in Taiwan has developed the optical technology to detect an early complication of diabetes called diabetic autonomic neuropathy, which is common among people with both Type 1 and Type 2 diabetes.
The condition progressively affects the autonomic nerves controlling vital organs like the heart and gastrointestinal system. This can lead to problems like fainting, incontinence, nausea, heart arrhythmias and an increased risk of bacterial infection.
Described in a paper published in The Optical Society (OSA)'s journal Applied Optics, the new technology is a small, wearable device called a pupillometer that can hang on a pair of eyeglasses and only weighs 78 grammes, slightly heavier than Google Glass.
Developed by a team at National Taiwan University Hospital, Hsin Chu branch and National Chiao-Tung University, the device is designed to be worn for a half hour or so in the doctor's office, during which time it would monitor a person's pupils.
By carefully measuring five parameters associated with the pupils, doctors may then be able to detect the earliest signs of diabetic autonomic neuropathy.
Currently the condition is often not detected until moderate nerve damage and organ dysfunction are present.
"Compared to the existing diagnostic techniques, the pupillometer is a more reliable, effective, portable and inexpensive solution for diagnosing diabetic autonomic neuropathy in its early stages," said Mang Ou-Yang, who led the research at National Chiao-Tung University.
The pupil is useful for detecting diabetic autonomic neuropathy due to the neurological conditions caused by the disease.
Like many organs, the eyes and pupil are dually innervated, receiving signals from both the parasympathetic and sympathetic divisions of the autonomic nervous system. These divisions control the pupil's circular and radial muscles, respectively.
The pupillometer, which is small enough to be mounted onto the front of a pair of glasses, works by emitting four coloured lights to stimulate the pupil.
A beam splitter attached to the device filters the visible light that is reflected from the eye to the device's camera, which processes the images to analyse the pupil's size.
The device measures 10 parameters related to pupil diameter and response time. Of those 10, the researchers found that five parameters were significantly different in people with diabetic autonomic neuropathy.
Ou-Yang said if clinical trials are successful, the pupillometer could be available by the end of the decade.